Centrifugal exerciser



Sept. 16, 1969 o. A. JUSTICE CENTRIFUGAL EXERCISER 4 Sheets-Sheet 1 Filed Dec. 17, 1965 INVIENTOR. Donald A. Justice *wwaafl a ATTORNEYS Sept. 16, 1969 o. A. JUSTICE CENTRIFUGAL EXERCISER 4 Sheets-Sheet 2 Filed Dec. 17, 1965 INVENTOR. Donald A. Justice w /ffi Ow vm ATTORNEYS Sept. 16, 1969 D. A. JUSTICE CENTRIFUGAL EXERCISER 4 Sheets-Sheet 5 Filed Dec. 17, 1965 IN V liNTOR. Donald A. Justice ATTORNEYS Sept. 16, 1969 D. A. JUSTICE 3,467,373

CENTRIFUGAL EXERCISER Filed Dec. 1'7, 1965 4 Sheets-Sheet 4 IIIIIIIIIIIII- r-QI Fig. 8 Q

IN VIL'NTOR.

lj nald 'A. Justice AT TORNEYS United States Patent US. Cl. 272-33 ABSTRACT OF THE DISCLOSURE The centrifugal apparatus includes an elongated frame which is supported for rotation at its central portion. The frame carries a cradle at one end which is adapted to accommodate a passenger and a counterweight disposed at the opposite end of the frame. The counterweight is adjustable to compensate for different passenger weights. The counterweight includes a rotatable flywheel' mounted for rotation about an axis parallel to the axis of rotation of the frame. A manual drive means is provided for rotating the frame and comprises a pedal device located on the cradle and driven by the passenger. The drive is transmitted from the pedals to the rotatable flywheel and drives the flywheel in one direction of rotation which in turn rotates the frame in the opposite direction.

vention will be hereinafter called a centrifugal exerciser.

It is anticipated that the centrifugal exerciser, the present invention, can be advantageously used 1n space travel,

and accordingly, another object of the invention is to provide a novel and improved centrifugal exerciser WhlCh is a'self-propelled unit capable of operating in -a zerogravity environment as in a spaceship.

' As more extensive trips into outer space are being 'planned, the physiological effects of prolonged living in a zero-gravity, weightless environment become a matter of concern. For example, it has been observed that an astronauts rate of heart beat will slow down significantly after'a few days in space, but will speed up considerably above normal as he is returning to earth. Another concern 1 is an undesirable loss of muscle tone in a prolonged weightless environment. It is generally conceded that these observed, and other physical changes can bring about-severe and even dangerous physical reactions after a prolonged trip into space.

It has been suggested that a space traveler can avoid the deleterious effects which may be produced by weightlessness through periodic and repeated exercises of a type which not only stimulate the individuals physique, but also produces a simulated gravitational effect on his body.

The natural and obvious mode of simulating gravity effects is to place an individual at the rim of a whirling ice apparatus to impose centrifugal forces upon his body during an exercise period. Such centrifugal forces may vary in intensity depending upon the speed of rotation of the apparatus and insofar as the individual is concerned, produce the same effect as if he were on the earths surface.

Although the concept of such means for maintaining the physical condition of spacecraft crews is generally accepted, the weight penalty of such apparatus appears at first to be prohibitive, not only because of the weight and bulk of the device itself but, more important, because of the weight of propellants required to cancel out the reaction of the device upon the spacecraft by use of the spacecraft altitude control system.

Accordingly, an object of the invention is to provide a novel and improved centrifugal exerciser which is a compact, lightweight unit, of a carefully balanced construction and which may be easily incorporated into a spaceship design.

Another object of the invention is to provide a novel and improved centrifugal exerciser for a spaceship which is manually operated by a passenger, commencing as from a position at rest, as within a spaceship, easily rotated to the speed which produces a desired centrifugal effect, and thereafter returned to the original resting position A further object of the invention is to provide a novel and improved centrifugal exerciser for a spaceship which is a self-contained, well-balanced unit which will not vibrate or wobble on its mounting spindle within the spaceship and which may be accelerated to any desired speed of rotation Without imposing torque upon its mounting spindle or on the spaceship.

Another important object of the invention is to provide a novel and improved centrifugal exerciser which may be used in a zero gravity environment and also may be used in a normal terrestrial gravity environment with slight modifications.

Another object of the invention is to provide a novel and improved centrifugal exerciser which can be built, tested and proven through the construction of a terrestrial unit, to produce a compact, efficient, reliable unit for zero-gravity use. i

A further object of the invention is to provide, in a centrifugal exerciser, a unique arrangement of counterweights and balancing members to produce a self-contained, fully-balanced apparatus with a minimum possible overall weight and bulk.

With the foregoing and other objects in view, all of which more fully hereinafter appear, my invention comprises certain constructions, combinations and arrangements of part and elements as hereinafter described, defined'in the appended claims and illustrated in preferred embodiments in the accompanying drawing, in which:

FIGURE 1 is a perspective view of a first embodiment of the centrifugal exerciser, illustrating the same as carrying a passenger and with broken lines at one portion indicating the manner in which thepassenger-carrying cradle section swings when the apparatus is in use.

FIGURE 2 is a fragmentary sectional detail of the counterbalancing portion of the apparatus as taken substantially from the indicated line 2-2 at FIG. 1.

FIGURE 3 is a fragmentary sectional detail of the central mounting pivot of the apparatus as taken substantially from the indicated line 3-3 at FIG. 1.

FIGURE 4 is a front perspective view of the passengercarrying cradle of the apparatus as taken substantially from the indicated arrow 4 at FIG. 1.

FIGURE 5 is a rear perspective view of the passengercarrying section of the apparatus as taken substantially from the indicated arrow 5 at FIG. 1.

FIGURE 6 is a fragmentary elevational detail view as taken from the indicated arrow 6 at FIG. 5.

FIGURE 7 is a side elevational view of a second embodiment of the centrifugal exerciser, which is especially adapted to be used in a zero-gravity environment.

FIGURE 8 is a reduced-scale, front elevational view of the exerciser illustrated at FIG. 7, wherein the apparatus is illustrated as being mounted within an annular housing as at an end of a spaceship compartment.

The improved centrifugal exerciser was conceived and developed to produce a terrestrial unit which can be easily modified for use in a zero-gravity environment, as in a spaceship. To accomplish this, the terrestrial unit was designed to rotate in a horizontal plane, about a vertical spindle axis, so that gravity forces on the apparatus would be normal to the plane of rotation, and would not produce components in this rotative plane. Accordingly, the balancing-out of gravity forces at each side of the vertical spindle axis produces a condition simulating a zerogravity environment in the horizontal plane of rotation.

The exerciser is, basically, a longitudinally-extended structure, mounted upon a central vertical spindle. It is adapted to carry a passenger at one side of the spindle and counterweights at the opposite side thereof. The apparatus must be carefully balanced upon this central spindle to avoid vibration and wobbling as it is rotated. Such balancing is of considerable importance since the comparatively light weight of the spaceship, wherein a zero-gravity unit may be used, simply cannot serve as a buttress to take care of irregularities of weight distribution in the apparatus. Also, the frame connection to the spindle must be substantially frictionless to prevent torque from being imparted to the spaceship as the exerciser is rotated. Moreover, the exerciser must be selfcontained in that external torque action cannot be used to initiate rotation and to later stop the rotation without disturbing the orientation of the spacecraft.

The physical phenomenon involved in rendering the exerciser a self-contained, self-operating unit involves the application of conservation of momentum and in this instance, the conservation of angular momentum. Accordingly, the invention includes the concept of providing a flywheel adapted to be at rest whenever the exerciser is at rest and to be rotated in one direction to rotate the exerciser in the opposite direction. In order to minimize the. overall weight of the apparatus, this flywheel is mounted away from the spindle to serve also as a counterweight. It thus serves a double function, to balance the apparatus, including a passenger, on the central pivot and to create angular momentum to rotate the apparatus.- As an exerciser, it is further contemplated that this flywheel will be rotated by efforts of the passenger through suitable drive mechanisms, as will be set forth in detail.

Referring more particularly to the drawing, theterrestrial unit of a centrifugal exerciser E is illustrated at FIGS. 1 to 6. A modified unit E,-for a zero-gravity environment, is illustrated at FIGS. 7 and 8, as will .be hereinafter further described. The exerciser E is formed as an elongated Y-frame 10 having a passenger-carrying cradle 11 at one end and a counterweight assembly 12 at the other end. The frame 10 is supported upon a central spindle 13 which, in turn, is mounted in a vertical post 14. The post, holding the spindle vertically, is formed with a flange 15 at its base to permit it to be securely anchored to a'floor, as by lug bolts 16 extending through suitable holes in the flange and into the floor.

The Y-frame 10 is formed of lightweight, tubular structural members suitably welded together. It includes a leg 20 at one side of the spindle to carry the counterweight assembly 12 and a pair of diverging arms 21 at the other side of the spindle to support the passenger cradle 11. The length of thelegs and arms is such as to provide a balance point at the crotch of the Y where the leg and arms come together. The frame includes a short, tubular sleeve 22 at this crotch which is suitably welded to the frame members to depend normally from the plane of the Y-frame and to hold the spindle 13. Reinforcing struts 23 connect the leg 20 and arms 21 with the lower end of the sleeve 22 to enhance thestrength and-rigidity of theassembly.

As seen in FIG. 3, the spindle 13 is a cylindrical rod which is stepped into sections of decreasing diameter. A base section 24, of maximum diameter, fits into a socketed plug 25 at the top of the post 14. Rivets 26 extending through thetop of the post hold these members together. An intermediate spindle section 27 of smaller diameter extends through and above the frame sleeve 22 and supports the frame by a pair of radial-thrust type bearings 28 on the spindle and within the sleeve. A lower bearing sets upon the shoulder 29 betweenthe base and inter-mediate sections of the spindle and is fitted into the lower .end of the sleeve 22. A spacer tube. 30 within the .sleeve separates the upper and lower bearings 28. The upper bear-ing-is at the top end of the sleeve and abutsagainst an inturned flange 31 of the sleeve to support the. frame 10 upon the spindle 13. Anupper. section 32 at theitop of the spindle, of further reduced diameter, holds a pair of bearings 33 which support idler sprockets, hereinafter described.

The counterweight assembly 12 at the'outward end of the leg 20 includes a flywheel 35 and a fixed weight 36. The flywheel serves two functiongfirst, to impart angular momentum to rotate the apparatus, and secondly,to supplement the fixed weight 36 in balancing the weight'of a passenger at the opposite end of the apparatus. Accordingly, the flywheel 35 is a comparatively heavy member with a heavy rim 37. It is mounted to -lie in a horizontal plane at the underside of the leg 20 and'is carried by a vertical shaft 38 which extends upwardly and through sleeve 39 near the end of the leg. The. sleeve 39 is'formed oftubular members extendingthrough and upstanding from the leg 20,. suitably welded into position onthe leg and further secured by a strut 40, as shown atzFIG. 2. The shaft 38 is mountedin this sleeve- 39 by a pair of bearings 41, one being positioned-at the bottomof-the sleeve againstFan inwardly turnedflange 42 and the other at the top of the-sleeve in a socket-'43::The top, portion of the shaft 38 extends above 'the sleeve to carryk-a drive sprocket, hereinafter describedxt f I The fixed-weight 36 is adjustablegto shift outwardly and inwardly fromthe leg 20 so.that itmaybe positioned to balance the apparatus to the different weights of the individuals who-.mayuseait. It is 'mounted upon a pair of threaded-rods 44which= lie in spaced parallelism with the leg 20,'!which each rod beingat oneside-of thewleg and extending beyond thetoutward-endrof'the leg. Each-outwardlyextended rod portion. fits into a hole: ,throughf the weight and is fastenedto the .;weight by'lock nuts 45:.The rods are also affixed tothe leg 20 bya pair-of rectangular brackets 46;"Each bracket is transversely mounted on the leg, with one-bracket being atzthegend. of: the-legend the other being spaceda short distanceinwardly-fromthe end thereof. Each bracket includes a, pair of holes, wherethrough the rods are extended; and the "rods'are. adjustably positioned upon these brackets-.byoppo sing,lock nuts-45-, as in the manner-illustrated at FIG. Where the apparatus isusedfrequently by manypersons and adjustments of. the fixedweight, 36 are also frequenhit is contemplated that the adjustments maybe controlled by. afservoamechanism, not shown, by. eliminating the nut, 45 which connect ,the rods, to the hrackets,46, and replacing them with shifting screws,aflixed to.a-.bracket and rotated by the servo mechanism. However, a manually adjustable apparatus, such as that illustrated, is preferable for the sake of simplicity where adjustments of this weight will not be excessively frequent.

The passenger cradle 11 is formed as a squat, U-shaped structure having a transversely disposed base tube 50 and a front arm 51 and a rear arm 52 upstanding from the respective ends of the base tube, as clearly seen in FIG. 5. The top ends of the cradle arms lie between and are pivotally connected to the outward ends of a frame arms 21 by a front pivot rod 53 and a rear pivot rod 54 which are secured to the respective arms 51 and 52 and are aligned on a common, transverse axis. These pivot rods are suspended, respectively, in a front bearing 55 and rear bearings 56 at the ends of the frame arms 21.

A passenger seat 57 is mounted upon the base tube 50 of the cradle at a position adjacent to the rear arm 52, the mounting being effected by a clamp head 58 at the underside of the seat. A balancing handle 59 is mounted upon a post 60 which is attached to the front arm 51 to extend rearwardly from that arm and place the handle at a position where a passenger may easily grip it. The post 60 is adjustable in length by providing two telescopically interconnected tubular portions which may be locked together as by a pin 61 extending through suitable registering holes in the post portions. To complete the cradle, a manual driving mechanism is mounted on the base tube 50, the preferred driving mechanism, as illustrated, is a pedal system similar to a bicycle drive, as will be hereinafter further described.

With this arrangement, the cradle 11 is suspended in the horizontally disposed frame to hang vertically therefrom when the apparatus is at rest, but to swing outwardly and away from the frame 10 as it is being'rotated, as in the manner indicated .by the broken-line portion of the arm 51, illustrated at FIG. 1. The centrifugal force producing this outward swing of the cradle is a horizontal component proportional to the speed of rotation of the apparatus. The gravity force, due to the weight of the passenger and cradle, is a vertical component which remains constant and which is not influenced by, nor influences, the horizontal centrifugal forces. Accordingly, excepting for a small unbalance due to the outward swing of the cradle as it speeds rotation, the horizontal components of forces and momentum effects on the apparatus, which vary according to the speed of rotation of the apparatus, will simulate the action of the apparatus in a Zero-gravity environment.

The manual drive includes a train of mechanisms which extend from foot pedals 62 at the lower front end of the cradle to the flywheel 35 at the opposite end of the apparatus, as best seen in FIG. 1. The first section of this train of mechanisms includes the pedals 62 at each side of a pedal shaft 63 which is mounted in a frame bearing 64 secured to the underside of the forward end of the base tube 50. A nest of three drive sprockets 65, of different diameters, is carried on this pedal shaft and a chain 66 is meshed upon one of the sprockets to extend rearwardly to mesh with one of a nest of rear driven sprockets 67, clearly shown in FIG. 4. These rear sprockets 67 are mounted upon a shaft 68 carried in a U-shaped bracket 69 which is clamped to the base tube 50 to extend rearwardly ofthe rear arm 52 of a cradle, as in FIG. 5. The pedals, driving sprockets 65, chain 66 and driven sprockets 67 are similar to a conventional bicycle drive. To obtain variable speeds of operation, the chain is shifted from one sprocket to another at either the front sprocket nest 65 or the rear sprocket nest by conventional bicycle derailing devices, generally indicated as 70 in FIGS. 4 and 5, which is regulated by controls 71 affixed to suitable spurs 72 upstanding from the base tube 50.

The nest of driven sprockets 67 is connected with a first bevel gear 73, on the shaft 68. This bevel gear meshes with a second bevel gear 74, as best seen in FIG. 5, which is mounted on the end of a shaft 75, perpendicular to the shaft 68 and paralleling the arm 52. This shaft 75 is mounted in bearings 76 secured to the arm 52 by clamp heads 77. A third bevel gear 78 is mounted at the top of the shaft 75 adjacent to the pivot rod 54 which connects the rear arm 52 of the cradle with the frame arm 21. A fourth bevel gear 79, an idler gear, is mounted upon an extension of this rear pivot rod 54 to. mesh with the third gear and also mesh with a fifth bevel gear 80' which is mounted upon a shaft 81 carried in a pivot block 82, as in FIG. 6, attached to the end of the rear frame arm 21, the block 82 also supporting the rear bearings 56, heretofore described. A strut 40 upstanding from the frame arm 21 reinforces this block 82 on the arm 21. It follows that swinging movements of the cradle 11 about the frame pivots rods 53 and 54 are possible with the bevel gears 78 and 80 at each side of the idler 79- remaining in mesh with idler and with the train of mechanisms being interconnected regardless of the position assumed by the cradle 11.

The shaft 81 upstands from the frame arm 21 within the bracket block 82 and a first frame sprocket 83 is mounted on shaft 81 above the fifth bevel gear 80. A chain 84 extends from the sprocket 83 above the arm 21 towards the crotch of the Y-frame to connect with a second sprocket 85 mounted upon the upper section 32 of the spindle 13, on a bearing 33. This second sprocket is interconnected with a third sprocket 86 also mounted upon the spindle section on another bearing 33. The sprocket group 85 and 86 thus idle on spindle 13. A chain 87 extends from this third sprocket 86 to a fourth sprocket 88 which is mounted upon the flywheel shaft 38 to complete the assembly.

The apparatus is simple to operate. Once it is balanced for a passenger, the passenger simply mounts the apparatus in the seat 57, and may secure himself therein with a safety belt 89, as indicated at FIG. 1. Also, a headrest 90, extending above the seat, is desirable to help hold the passengers head in a fixed position. To commence, he shifts the chain 66 onto any selected pair of sprockets 65 and 67 and simply commences to turn the mechanisms with the foot pedals 62 and thereby commence to rotate the flywheel 35. The rotation of the flywheel effects a counter rotation of the apparatus about the spindle 13. To increase the speed of rotation, the passenger may shift chain 66 to other pairs of sprockets 65 and 67, the same as a bicycle rider shifts the chain on the bicycle sprockets. As the speed of rotation is increased, the passengers cradle swings outwardly, and the cradle is adapted to swing to an angle of approximately 75 degrees from the vertical rest position. The limiting swing is where the teeth of the third bevel gear 78 commences to contact the teeth of the fifth bevel gear 80. Accordingly, a centrifugal force of approximately twice gravity is possible with the apparatus. To prevent an excessive upswing from clashing the bevel gears 78 and 80', a stop, not shown, may be mounted upon a frame arm 21 adjacent to the bearing, 55 or 56, to contact the end of the cradle arm, 51 or 52.

To stop the apparatus, the operator need only to slow down and stop turning the pedals 62. In a more elaborate construction than that shown, a ratchet mechanism at the pedal, or elsewhere, may be used to permit the train of mechanisms to be disengaged when the passenger stops pedaling and a brake may be used to stop the spinning of the flywheel.

The exerciser E, illustrated at FIGS. 1 to 6, may be easily modified for use in a zero-gravity environment by an actual simplification of the construction of the unit.

The exerciser E, illustrated at FIGS. 7 and 8, is exemdirectly connected to the bevel gear 80, as illustrated. It is to be noted that the elimination of the idler bevel gear reverses the direction of flywheel rotation with respect to rotation of the foot pedals, and in order to rotate the exerciser forwardly, with respect to the passengers position, the foot pedals will have to be turned in a direction which is normally backwards. However, if reverse pedaling is undesirable, the second bevel gear 74' may be relocated as to the position indicated in broken lines at FIG. 7 by suitable modifications of the bracket 69 and the shafts 68 and 75.

This apparatus may be mounted in a cylindrical end of a spaceship S to rotate in a plane parallelto the endwall 91 of the ship. The spindle 13 of the apparatus is mounted in a post 14' which, in turn, is mounted at the center of the endwall 91. This post may be rigidly aflixed to the ship endwall 91, as by flange 15 attached thereto by bolts 16'. Where the apparatus is mounted in a zerogravity environment and angular momentum is imparted to it, as by rotation of the flywheel, without any'other displacement, the unit will naturally commencerotating about an axis which is a true centroid of the'apparatus-The adjustments to the fixed weight 36 will place the centroid of the apparatus as close as possible to the axis of the spindle 13. If this is not done, excessive vibration will'be iniparted to the spaceship as the exerciser is rotated should the post 14' be rigidly aflixed to the wall. .1

It is important that this apparatus be dynamically balanced when a passenger is mounted in the seat 57, not only with respect to radial centrifugal actionsfromia centroid as at the axis of the spindle 13, but also .with respect to acceleration movements of portions of thesystern parallel to the spindle axis. This latter action tends to create a wobbling of the exerciser upon the spindle. Accordingly, it is important that the center of gravity of the counterweight assembly at one side of the apparatus and of the passengers cradle and passenger therewithin at the other side of the apparatus be at diametrically-opposing points which would lie on a line which intersects and is normal to the spindle axis. To provide such, the cradle arms 51' and 52' may be provided with offsets 94 to facilitate lining up and balancing the apparatus.

While I have now described my invention in considerable detail, it is obvious that others skilled in the art can build and devise alternate and equivalent constructions which are nevertheless within the spirit and scope of my invention. Hence, I desire that my protection be limited, not by the constructions illustrated and described, but only by the proper scope of the appended claims.

What is claimed is:

1. A centrifugal exerciser mounted upon a-spindle and being adapted to rotate freely thereabout, and comprising, in combination therewith, an elongated frame having -a spindle mount at its central portion, a cradle at one end of the frame adapted to support a-passenger','a' counterweight assembly at the other end of the frame adapted to balance the apparatus upon the spindle with a passenger in the cradle, a flywheel carried upon the frame and having its axis parallel to the spindle axis and being adapted to be rotated with respect to the frame'in one" direction and thereby impart rotation to the frame in the opposite direction, and a manually operable drive means operable 2. A centrifugal exerciser mounted upon a spindle and being adapted to rotate thereabout, and comprising, in combination therewith, an elongated frame having asubstantially frictionless spindle mount at its central port-ion, a cradle at one end of the frame adapted to support a passenger, a counterweight assembly'at the other end'of frame in one direction to impartrotation to the frame in I the opposite direction, means on the fr'ameadapte'd to rotate the flywheel, and said flywheel rotating means extends'from the'flywheel' to thepassengers cradle and includes manually operable driving means whereby the flywheel is rotated manually, as by the efforts of the passenger in the cradle. A

3. In the exerciserdefined in claim 2, wherein said counterweight assembly includes a fixed weight attached to .the frame. and adapted to be shifted'along thejframe, t'owardsand away fromthe spindle and set atasele'cted position on -the frame to counterbalance-theweight of a specific. passenger. 1 t

4. In the exerciser definedin claim 2, wherein the spindle is mounted upon a vertical post and the frame is adapted -torotate in a horizontal plane about the post; and wherein the passengers cradle is pivotally suspended from the frame and is thereby adapted to hang from the end of the frame when the apparatus. is not-rotatin'g;.but is adapted to swing outwardly when the apparatus is rotating about the spindle.

' 5. In the exerciser defined in claim 4, wherein said frame i -sh p d' t j si dl in' ns. b in ai ia e tl h crotch of theY an'dwith the fc radle being formed as a U- shaped L'frame pivotally suspended between the" arm'sfof theY. Y 6. In the exerciser definetl in' claim 2, wherein said frame is Y-shap'ed with the spindle means 'adjacentto the crotch of the Y, the cradle is forined asfa' U-shape'd frame suspended between the arms, of Y andgincl udjes'a'pafpsenger seat at one end thereof and driving meansiii front of the passengers seat adapted to.be operated by the passenger, said driving means being operatively connected to the flywheelandbeing adapted to rotate the'samew 7. -In the exerciserset-fortl1 in :cIaimfiywherein-said driving'means includes a crankingmeans at the passen- -gers= cradleand a a 1 train- "of mechanisms interconnecting the cranking-means and the flywheel-y 1 1 w -8. -In the exerciser set'forthin claim 6, wherein said driving means includes apedal driveadapted to be turned by the passenger,.a train ofmechanismssinterconnecting from the-pedaldriveto theiflywheel, includingsprockets .and chain means paralleling the frame. I 4

9. In the exerciser set forth in claim '6, wherein said driving means'includes apedal. drive at the baseaof the set forth in claim'j9, ineluding :i ller cradle to'hang vertically when thefranie is oriianted liorizontally upona vertically axisedfispindle and to swingtoutwardlyfrom the' vertical'fas'the ame is rotatedabout the spi dl x '1 l :3 '1 nth-'11 A centrifugalexerciser for a zermgravityenvirongment', asin a's'paceshipg and comprising? w a memberadapted tobe attached*to thewall o the 'ship'to -normallyrestrain'theapparatus"- an elongated frame having a Y-sha'ped configuration with a'central leg at one =side=and spreading arinsroppositely' thereto; '1 r '2 a low-friction-bearingtrttached to thecentr'al -pdrtion of said frame pivotally engaging-said member and I 'h'avingan' axis which is-normal tothe plane of *said frame; 5 z =a U-"shaped' -passenger-carrying cradle having its arms connected with the ends of-"the arms of the Y-frame counterweight assembly being proportioned to place the centroid of the system substantially at the hearing axis when a passenger is in place in the cradle; and

manually driven means at the passengers cradle extending to the flywheel, and adapted to be operated by a passenger to rotate the flywheel, whereby rotation of the flywheel imparts a counter rotation of the frame.

References Cited UNITED STATES PATENTS 548,450 10/ 1895 Norcross 272-33 Haeussermann et a1.

ANTON O. OECHSLE, Primary Examiner ARNOLD W. KRAMER, Assistant Examiner US. Cl. X.R. 

